Telescopic joint with interchangeable inner barrel(s)

ABSTRACT

Embodiments disclosed herein relate to an apparatus including a first inner barrel of a telescopic marine riser and a first locking mechanism to releasably lock an upper end of the first inner barrel to the telescopic marine riser or a second inner barrel. In another aspect, embodiments disclosed herein relate to a method including assembling a telescopic marine riser, replacing at least one inner barrel of a telescoping marine riser with a corresponding replacement inner barrel of a different length, and reassembling the telescoping marine riser with the replacement inner barrel.

RELATED APPLICATIONS

This application claims the benefit of US Provisional Application havingSer. No. 62/013,860 filed Jun. 18, 2014, which is incorporated byreference in its entirety.

BACKGROUND

Drilling, production and completion of offshore wells from a floatingplatform, e.g., a vessel, tension leg platform, etc., is conductedthrough a riser assembly which extends from the platform to the wellheadon the sea floor. The riser assembly includes a series of pipe sectionsor barrels connected end to end. Marine drilling risers provide aconduit through which materials may flow between a platform and awellbore. While the platform from which the wellbore activities arebeing conducted is maintained as nearly as possible in a fixed positionabove the wellhead, there is some variation in this relationship, suchthat there is relative lateral and vertical shifting between theplatform and the wellbore. Accordingly, the riser assembly accommodatesthis relative movement between the platform and the wellhead as well asforces acting on the riser assembly from waves, currents and the like.

FIG. 1 shows a conventional marine drilling system having an outerbarrel 16 of a telescoping riser section whose lower end is coupled tothe top of a fixed length of riser (not shown) that extends to a subseawellhead (not shown). The telescoping riser section is supported by atension ring 20 coupled to the outer barrel 16. The tension ring 20 is atype of buoyancy component for supporting at least part of the weight ofthe telescoping riser once connected to a well head and to put tensionon the riser. The tension ring 20 is coupled to the outer barrel 16 andincludes cables (not shown) that extend to the floating drillingplatform 11 in order to transfer some of the buoyancy thereof to thetension ring 20 to support at least part of the weight of thetelescoping riser in the body of water. An inner barrel 14 slidably,sealingly engages the interior of the outer barrel 16. Specifically, aconnector, for example a packing element 18 may be slidably engaged withthe inner barrel 14. A lower end of the packing element 18 ispermanently coupled to an upper end of the outer barrel 16. Thus, thelength of the riser may be changed in order to compensate for heave ofthe drilling platform 11. The riser may also be moved laterally tocompensate for lateral motion of the drilling platform 11. The upper endof the inner barrel 14 is permanently coupled to a flange 17. The flange17 allows the telescoping riser section to easily connect to a flexjoint 12 and a diverter 10, disposed at the top of the marine riser.

Currently, in the art, if the length of the telescopic riser is to beshortened, the inner barrel 14 is cut to remove from flange 17 and thecut section of the inner barrel 14 is removed to adjust the length. Theremaining sections of the inner barrel are welded together to bring thelength of the inner barrel to the desired length. If it is desired tolengthen the inner barrel, the inner barrel may be cut into two sectionsand a tubular section having the same characteristics (i.e. inner andouter diameters) as the inner barrel may be welded between the twosections of the cut inner barrel.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an example embodiment of a marine drilling system using ariser;

FIG. 2 shows an example embodiment of a marine drilling system accordingto the present disclosure;

FIGS. 3-5 show example embodiments of locking mechanisms according tothe present disclosure.

DETAILED DESCRIPTION

A riser assembly comprises a series of pipe sections or telescopingbarrels connected end to end. In one aspect, embodiments disclosedherein relate to an apparatus and method for changing the length of atelescopic marine riser without physically damaging the barrels (e.g.,cutting and/or welding). Specifically, embodiments disclosed hereinprovide a telescopic marine riser having interchangeable barrels.

In one aspect, embodiments disclosed herein relate to an apparatushaving a first inner barrel of a telescopic marine riser and a firstlocking mechanism to releasably lock an upper end of the first innerbarrel to the telescopic marine riser or a second inner barrel.

In another aspect, embodiments disclosed herein relate to an apparatushaving an outer barrel of a telescopic marine riser, a first innerbarrel slidingly engaged with the outer barrel, a first connectorcoupled to an upper end of the outer barrel, wherein the first innerbarrel is slidingly engaged with the first connector, and a firstlocking mechanism coupled to a lower end of at least one of a firstflange or a second connector, the first locking mechanism configured toreceive an upper end of the first inner barrel and releasably lock thefirst inner barrel to a top portion of the marine riser or a secondinner barrel.

In another aspect, embodiments disclosed herein relate to a method thatincludes coupling a first locking mechanism to a first connector or amarine riser; and releasably locking an upper end of a first innerbarrel to the first locking mechanism. The method may further includecoupling a lower flange to a lower end of an outer barrel of a marineriser, pre-assembling a first inner barrel by slidingly engaging thefirst inner barrel to a first connector to form a pre-assembled firstinner barrel, coupling a lower end of the first connector to an upperend of the outer barrel, wherein the pre-assembled first inner barrel isslidingly engaged with the outer barrel, and locking an upper end of thefirst inner barrel to a first locking mechanism, wherein the firstlocking mechanism is coupled to a lower end of at least one of an upperflange coupled to a top portion of the marine riser, or a secondconnector slidingly engaged with a second inner barrel.

In another aspect, embodiments disclosed herein relate to a method, themethod includes assembling a telescopic marine riser, replacing at leastone inner barrel of a telescoping marine riser with a correspondingreplacement inner barrel of a different length, and reassembling thetelescoping marine riser with the replacement inner barrel.

A telescopic riser 100 section according to the present disclosure isshown schematically in FIG. 2. As used herein, the term “telescopicriser” and “telescopic marine riser” are used interchangeably to referto a portion of a marine riser assembly having telescoping barrels. FIG.2 does not show all components of the marine riser assembly, such as thedrilling platform or the diverter for clarity of the illustration. Thetelescopic riser 100 includes an outer barrel 116, and two inner barrels114-1 and 114-2. In other embodiments, the telescopic riser 100 mayinclude one outer barrel and more than two inner barrels. Each innerbarrel 114-1, 114-2 is slidingly engaged with a connector 118-1 and118-2, such that first inner barrel 114-1 is slidingly engaged withfirst connector 118-1 and second inner barrel 114-2 is slidingly engagedwith second connector 118-2, i.e. the position of the connectors 118along the respective inner barrel may change. Connector 118-1 may becoupled to an upper end of second inner barrel 114-2 and connector 118-2may be coupled to an upper end of outer barrel 116. As shown, the firstand second connectors 118-1, 118-2 are positioned at a lower end offirst and second inner barrels 114-1, 114-2, respectively. However, oneof ordinary skill in the art will appreciate that because the connectorsare slidingly engaged with the inner barrels, the connectors may bepositioned at an upper end of the inner barrels in other configurations.According to some embodiments, the connector may be a packing element.Each of the outer barrel 116 and inner barrels 114-1, 114-2 are arrangedend-to-end, such that the first inner barrel 114-1 is slidingly engagedwith the second inner barrel 114-2 and the second inner barrel 114-2 isslidingly engaged with the outer barrel 116.

As seen in FIG. 2, first inner barrel 114-1 is coupled to a lower end ofupper flange 117. The upper flange 117 allows a connection between thetelescopic riser 100 and a top portion of the marine riser assembly (notshown) including, for example, a flex joint, a diverter, and a drillingplatform. A first locking mechanism 121-1 may be coupled to a lower endof upper flange 117. The first locking mechanism 121-1 may bepermanently coupled to the lower end of the upper flange 117 by, forexample, welding or machining from a single integral piece. In someembodiments, the upper flange 117 may be integrally formed with thelocking mechanism 121-1. The first inner barrel 114-1 may be releasablylocked to the upper flange 117 with the first locking mechanism 121-1.

Still referring to FIG. 2, the first connector 118-1 may be slidinglyengaged with the first inner barrel 114-1; in other words, the firstconnector 118-1 may slide along the length of first inner barrel 114-1.The first connector 118-1 includes a second locking mechanism 121-2disposed at a lower end thereof. The second locking mechanism 121-2 maybe permanently coupled to or integrally formed with the first connector118-1. The second locking mechanism 121-2 may receive an upper end ofthe second inner barrel 114-2, such that the second inner barrel 114-2is releasably locked to the second locking mechanism 121-2 of the firstconnector 118-1. Because the first connector 118-1 is releasably lockedto an upper end of the second inner barrel 114-2, the first inner barrel114-1 is also slidingly engaged with the second inner barrel 114-2. Inother words, as first connector 118-1, second locking mechanism 121-2,and second inner barrel 114-2 slide along the length of the first innerbarrel 114-1, the inner barrel 114-1 may fit within and stroke in andout of the second inner barrel 114-2.

The second inner barrel 114-2 may be slidingly engaged with a secondconnector 118-2. According to the embodiment shown in FIG. 2, a thirdlocking mechanism 121-3 may be permanently coupled to or formedintegrally with the second connector at a lower end thereof. The thirdlocking mechanism 121-3 may receive an upper end of the outer barrel116, such that the outer barrel 116 is releasably locked to the thirdlocking mechanism of the second connector 118-2. Because the secondconnector 118-2 is releasably fixed to an upper end of the outer barrel116, the second inner barrel 114-2 is also slidingly engaged with theouter barrel 116. In other words, as second connector 118-2, thirdlocking mechanism 121-3, and outer barrel 116 slide along the length ofthe second inner barrel 114-2, the second inner barrel 114-2 may fitwithin and stroke in and out of the outer barrel 116. In someembodiments, the bottommost barrel, the outer barrel 116, may be coupledto a lower flange 115. The lower flange 115 is provided to allow aconnection between the telescopic riser 100 and a bottom portion of themarine riser assembly, including for example, a fixed length riser, andthe wellbore.

According to some embodiments, the telescopic marine riser may includeany number of inner barrels. For example, the telescopic marine risermay include a first inner barrel slidingly engaged with the outerbarrel, where an upper end of the first inner barrel is releasablylocked to a first locking mechanism, where the first locking mechanismis coupled to a lower end of an upper flange, which is coupled to a topportion of the marine riser (not shown). According to other embodiments,three or four inner barrels may be included in the telescopic riser 100and connected as described above with respect to FIG. 2, such that theuppermost inner barrel is engaged with the locking mechanism of theupper flange and the bottommost barrel or outer barrel is engaged withthe lower flange. One having ordinary skill in the art will understandthat more than four inner barrels may be included in the telescopicmarine riser without departing from the scope of the present disclosure.

The locking mechanisms 121 of the telescopic riser 100 are substantiallytubular members that may be coupled to a lower end of an upper flange117 and/or a lower end of a packing element 118, for example, connectors118-1 and 118-2. The locking mechanisms 121 may be permanently coupled,for example, welded or integrally formed, with a lower end of an upperflange 117 and/or a lower end of a packing element 118. Referring toFIGS. 3-5, each locking mechanism 121 includes a body 128 and areleasable mechanical fastener, for example internal threads (FIG. 3), aplurality of screw receiving apertures 122 (FIG. 4), or a plurality ofslots 124 to provide a releasable locked connection (FIG. 5). The upperend of the corresponding inner barrel 114 or outer barrel 116 includes acomplementing mating mechanical fastener, for example, external threads(FIG. 3), a plurality of screw receiving apertures 122 (FIG. 4), and aplurality of protrusions corresponding to the plurality of slots 124 ofthe locking mechanism 121 (FIG. 5). One having ordinary skill in the artwill appreciate that the locking mechanism may use other mechanicalfasteners without departing from the scope of this disclosure.

Referring to FIG. 3, the locking mechanism 121 may include internalthreads 125 formed on the body 128 of the locking mechanism 121, and theupper end of the inner barrel 114 may have corresponding externalthreads 125 configured to engage the internal threads. In order tosecure the inner barrel 114 to the upper flange 117 or connector 118,the inner barrel 114 may be inserted in the locking mechanism 121, androtated to tighten the threaded connection. In order to release theconnection, the inner barrel 114 may be rotated in the oppositedirection relative to the locking mechanism 121 to loosen the threadedconnection.

Referring to FIG. 4, the locking mechanism 121 may have a plurality ofscrew receiving apertures 122-1 in a wall of the body 128 of the lockingmechanism 121, and the upper end of the inner barrel 114 may also have aplurality of screw receiving apertures 122-2 configured to align withthe screw receiving apertures 122-1. In order to secure the inner barrel114 to the locking mechanism 121 of the upper flange 117 or connector118, each of the screw receiving apertures 122 of the inner barrel 114and the locking mechanism 121 may be aligned and a screw (not shown) maythen be inserted into each of the aligned screw receiving apertures 122to lock the inner barrel 114 to the locking mechanism 121 of the upperflange 117 or connector 118. In order to release the connection, thescrews may be removed from the screw receiving apertures 122. One ofordinary skill in the art will appreciate that other mechanicalfasteners, such as bolts, pins, etc. may be used with the screwreceiving apertures.

Referring to FIG. 5, the locking mechanism 121 may have a plurality ofslots 124 disposed on a lower edge of the body 128 of the lockingmechanism 121, and the upper end of the inner barrel 114 may have aplurality of protrusions 126 corresponding to the plurality of slots124. The plurality of slots 124 may be disposed in a wall of the lowerend of the body 128. According to some embodiments, the plurality ofprotrusions 126 may be spring loaded. In order to secure the innerbarrel 114 to the locking mechanism 121 of the upper flange 117 orconnector 118, the slots 124 of the locking mechanism 121 may be alignedwith the protrusions 126 of the inner barrel 114. The protrusions 126may then be inserted into the slots 124 and secured into place, therebyreleasably locking the inner barrel 114 to the upper flange 117.According to some embodiments the inner barrel 114 may be rotated withrespect to the locking mechanism 121 to release the spring loadedprotrusions 126 and secure the locked connection. In order to releasethe connection, the inner barrel 114 may be rotated in the oppositedirection, thereby compressing the spring loaded protrusions 126, andthe inner barrel 114 may continue to be rotated following the path ofslots 124 until the inner barrel 114 is disengaged from the lockingmechanism 121.

Although the above examples are described with respect to the lockingmechanism 121 and the inner barrel 114, one having ordinary skill in theart would understand that any of the above examples may be implementedwith any combination of locking mechanisms and barrels.

Assembly of the telescopic marine riser as described with respect toFIG. 2 may include pre-assembly of the first inner barrel 114-1 to afirst connector 118-1 to form a pre-assembled first inner barrel. Oncethe first inner barrel 114-1 is pre-assembled, the first connector 118-1may be slidingly engaged with the first inner barrel 114-1. In otherwords, the first connector 118-1 may be able to slide along the lengthof the first inner barrel. In embodiments where the second lockingmechanism 121-2 is permanently coupled to the first connector 118-1, thelocking mechanism 121-2 may be permanently coupled to the firstconnector 118-1 prior to pre-assembly of the first inner barrel 114-1.In other words, the pre-assembled first inner barrel 114-1 may beslidingly engaged with the first connector 118-1 having a second lockingmechanism 121-2 coupled thereto.

Pre-assembly may be repeated for the second inner barrel 114-2 and thesecond connector 118-2 to form a pre-assembled second inner barrel. Onehaving ordinary skill in the art will understand that pre-assembly ofthe second inner barrel 114-2 (i.e. a barrel disposed lower on thetelescopic marine riser than the first inner barrel 114-1) to the secondconnector 118-2 may be performed prior to assembly of the first innerbarrel without departing from the scope of the present disclosure.According to embodiments having more than two inner barrels,pre-assembly may be completed for each inner barrel. For embodimentshaving a single inner barrel, pre-assembly may be completed for thefirst inner barrel.

Once pre-assembly of at least the bottommost inner barrel, for example,the second inner barrel 114-2 is completed, a lower end of the secondconnector 118-2 may be coupled to an upper end of the outer barrel 116.This allows the second inner barrel 114-2 to be slidably engaged withinthe outer barrel 116. According to some embodiments, a locking mechanism121-3 may be disposed at a lower end of second connector 118-2, suchthat the second connector 118-2 is releasably locked to the outer barrel116 according to the examples provided above with respect to FIGS. 3-5.

The upper end of the second inner barrel 114-2 may be coupled to thefirst connector 118-1 (which is pre-assembled to the inner barrel114-1). This allows the first inner barrel 114-1 to be slidably engagedwith the second inner barrel 114-2. As shown in FIG. 2, the secondlocking mechanism 121-2 is disposed at a lower end of the firstconnector 118-1. The upper end of the second inner barrel 114-2 may bereleasably locked to the second locking mechanism 121-2 according to theexamples provided above with respect to FIGS. 3-5.

The upper end of the first inner barrel 114-1 may be coupled to a lowerend of the upper flange 117. As shown in FIG. 2, the first lockingmechanism 121-1 is disposed at a lower end of the upper flange 117. Theupper end of the first inner barrel 114-1 may be releasably locked tothe first locking mechanism 121-1 according to the examples providedabove. Although the above described method of assembly is presented in aparticular order, one having ordinary skill in the art will understandthat assembly of the telescopic riser 100 may be completed even if thesteps are performed out of the order presented above.

Once a telescopic drilling riser has been assembled, the assembledtelescopic drilling riser may be used at a drill site. According to someembodiments, it may be desirable to change the length of the outerbarrel 116 and/or inner barrels 114-1, 114-2 of the telescopic drillingriser, for example, if the requirements of the drill site change or thetelescopic marine riser is relocated to a new drill site. Thus, at leastone inner barrel of the telescopic marine riser may be replaced with acorresponding replacement inner barrel of a different length. Then thetelescopic marine riser may be reassembled with the replacement innerbarrel.

In order to replace at least one inner barrel of the telescopic marineriser, the original telescopic marine riser may be disconnected from themarine riser assembly and pulled to the surface for disassembly. Thenumber of original barrels to replace as well as the number and lengthof the replacement inner barrels to be included in the telescopic riser100 may be determined based on the new requirements of, for example, anew drill site. The term “replacement inner barrel” as used hereindescribes an inner barrel that was not a part of the original telescopicmarine riser assembly, in other words a replacement inner barrel isstructurally similar to the inner barrels 114 described above but areplacement inner barrel may have a different length. For example, ifthe distance between the surface of the water and the wellhead of thewellbore is greater than the original drill site, longer replacementbarrels may be selected, an additional inner barrel may be added or acombination of longer barrels and an additional inner barrel may beused. If the distance between the surface of the water and the wellheadof the wellbore is less than the original drill site, shorterreplacement barrels may be selected or an inner barrel may be removedfrom the original telescopic marine riser assembly. Once the number ofinner barrels to replace has been determined, said inner barrels may beunlocked from the locking mechanism and removed from the originaltelescopic marine riser assembly as described with respect to FIGS. 3-5above.

The new telescopic marine riser may be assembled with the replacementinner barrels. Pre-assembly of the determined number of replacementbarrels may be performed by slidingly engaging a first replacementbarrel to a first connector to form a first pre-assembled replacementinner barrel. Once the determined number of replacement barrels has beenpre-assembled, the first connector of the first pre-assembledreplacement barrel may be coupled to the outer barrel of the existingtelescopic marine riser assembly. According to some embodiments, not allof the inner barrels of the original telescopic riser 100 are replaced,therefore, the first pre-assembled replacement barrel may be coupled toan existing inner barrel of the original telescopic marine riser. Thefirst connector may include a first locking mechanism at a lower end.Thus, the inner barrel or outer barrel of the original telescopic riser100 may be removably locked to the first connector of the firstreplacement inner barrel. Coupling a connector to the telescopic riser100 assembly and locking said connector to the telescopic riser 100assembly may be repeated for the determined number of inner barrels. Theuppermost pre-assembled replacement inner barrel may be coupled to anupper flange. Although the above described method of assembly has beendescribed in a particular order, one having ordinary skill in the artwill understand that assembly of the telescopic marine riser with thereplacement inner barrels may be completed even if the steps areperformed out of the order presented above.

Although the preceding description has been described herein withreference to particular means, materials and embodiments, it is notintended to be limited to the particulars disclosed herein. Rather, itextends to all functionally equivalent structures, methods and uses,such as are within the scope of the appended claims.

What is claimed is:
 1. An apparatus comprising: a first inner barrel ofa telescopic marine riser; and a first locking mechanism to releasablylock an upper end of the first inner barrel to the telescopic marineriser or a second inner barrel.
 2. The apparatus of claim 1, wherein thefirst locking mechanism releasably locks the first inner barrel to afirst flange coupled to the telescopic marine riser.
 3. The apparatus ofclaim 1, wherein the first locking mechanism releasably locks the firstinner barrel to a first connector, the first connector slidingly engagedwith the second inner barrel.
 4. The apparatus of claim 3, wherein thesecond inner barrel is slidingly engaged with the first inner barrel. 5.The apparatus of claim 3, further comprising a second locking mechanism,wherein the second locking mechanism releasably locks an upper end ofthe second inner barrel to a first flange coupled to the top portion ofthe telescopic marine riser.
 6. The apparatus of claim 1, furthercomprising: an outer barrel slidingly engaged with the inner barrel; anda second connector coupled to an upper end of the outer barrel, whereinthe first inner barrel is slidingly engaged with the second connector.7. The apparatus of claim 1, wherein the first locking mechanism is atubular member, wherein a lower end of the tubular member includes oneselected from a group consisting of internal threads, a screw receivingapertures, and a plurality of slots.
 8. The apparatus of claim 7,wherein the upper end of the first inner barrel includes one selectedfrom a group consisting of external threads, a plurality of screwreceiving apertures, and a plurality of protrusions corresponding to theplurality of slots of the first locking mechanism.
 9. The apparatus ofclaim 1, further comprising a plurality of inner barrels each slidinglyengaged to a corresponding connector, wherein the an upper end of anuppermost inner barrel is engaged with a first flange of the telescopingmarine riser and an upper end of each remaining inner barrel is engagedwith a connector disposed between each remaining inner barrel.
 10. Amethod comprising: coupling a first locking mechanism to a firstconnector or a marine riser; and locking releasably an upper end of afirst inner barrel to the first locking mechanism.
 11. The method ofclaim 10, wherein the locking comprises threadably engaging the upperend of the first barrel to the first locking mechanism.
 12. The methodof claim 10, wherein the locking comprises aligning a plurality ofapertures disposed on the first locking mechanism with a plurality ofapertures disposed on the upper end of the first inner barrel andsecuring the first locking mechanism to the first inner barrel bydisposing a mechanical fastener in at least one of the aligned pluralityof apertures.
 13. The method of claim 10, wherein the locking comprisessliding a plurality of protrusions disposed on an outer diameter of theupper end of the first inner barrel into a corresponding plurality ofslots disposed on the first locking mechanism.
 14. The method of claim10, further comprising: pre-assembling the first inner barrel byslidingly engaging the first inner barrel to a second connector to forma pre-assembled first inner barrel; and coupling a lower end of thesecond connector to an upper end of an outer barrel, wherein the firstinner barrel is slidingly engaged with the outer barrel.
 15. The methodof claim 10, wherein the first locking mechanism is coupled to the firstconnector, the method further comprising: pre-assembling a second innerbarrel by slidingly engaging the second inner barrel to the firstconnector to form a pre-assembled second inner barrel; and locking anupper end of the second inner barrel to a second locking mechanism,wherein the second locking mechanism is coupled to an upper flange ofthe marine riser.
 16. A method comprising: assembling a telescopicmarine riser; replacing at least one inner barrel of a telescopingmarine riser with a corresponding replacement inner barrel of adifferent length; and reassembling the telescoping marine riser with thereplacement inner barrel.
 17. The method of claim 16, wherein thereplacing comprises: determining a number of inner barrels to replacefrom the original marine riser assembly; unlocking a first inner barrelfrom an upper flange; and repeating the unlocking for the determinednumber of inner barrels.
 18. The method of 16, wherein the reassemblingcomprises: pre-assembling the determined number of replacement innerbarrels by slidingly engaging a first replacement inner barrel to afirst connector to form a first pre-assembled replacement inner barrel;coupling the first connector of the first pre-assembled replacementinner barrel to at least one of an upper end of an outer barrel or anupper end of a pre-assembled inner barrel; locking an upper end of thefirst pre-assembled replacement inner barrel to a first lockingmechanism, wherein the first locking mechanism is coupled to a secondconnector of a second pre-assembled inner barrel; and repeating thecoupling and locking the upper end of a pre-assembled replacement innerbarrel to a corresponding locking mechanism for the determined number ofreplacement inner barrels, wherein an uppermost pre-assembledreplacement inner barrel is locked to a first flange.
 19. The method ofclaim 16, wherein at least two inner barrels of the telescoping marineriser are replaced.
 20. The method of claim 16, wherein a length of thereplacement inner barrel is determined based on the requirements of anew drilling location.